I'm willing to bet that no one can prove that OBL is actually in Afghanistan. For all we know he could be back in the Sudan or in Uganda. He may even turn up for a visit to DIsneyland. I believe that he has many stand-ins, and can move through the Islamic world without hitting CIA trip wires. Anyone could pass into the US! Remember SHeik Abdul Rahman of WTC I fame? He was on numerous watch lists and still made it in. SInce we let in 14 SYrian student pilots last week(learning all the good sites in the US), it seems we have learned very little. Osama is like Waldo.
OBL's #2, Zawahiri, the man behind the murder of Anwar Sadat, visited the USA in the 90s also, even though he was on every watch list.
If we can't keep these guys out of the USA, how can we pretend to know if OBL is moving from Afghanistan to Somalia or Sudan or Pakistan?
We can't.